ENTAMAXIN SUSPENSION

Indications

• Amebiasis
• Trichomoniasis
• Giardiasis
• Anaerobic bacterial infections
• Bacterial vaginosis
• Clostridium difficile infection

Dosage

Children: For children aged 1 month to 11 years, 7.5 mg/kg every 8 hours for 7 days (maximum dose 400 mg). For children aged 12-17 years, 400 mg every 8 hours for 7 days.

Adults: 1 g three times a day for 3 days, then 1 g twice daily for a total treatment duration of 7 days. In cases of Clostridium difficile infection, treatment may extend to 10 days.

Mechanism of action

The exact mechanism of action of metronidazole is not fully established. However, it is believed that anaerobic bacteria and protozoa reduce metronidazole to reactive intermediates that bind to DNA and inhibit nucleic acid synthesis, leading to cell death. Metronidazole is selectively activated in anaerobic conditions, making it effective against obligate anaerobes.

Pharmacodynamics

Metronidazole exhibits both antibacterial and antiprotozoal activities, effectively treating infections caused by anaerobic bacteria. It demonstrates significant antibacterial activity against most obligate anaerobes but is less effective against facultative anaerobes and obligate aerobes. The drug's cytotoxic effects result from DNA strand damage in susceptible microorganisms, which can lead to cell death. Caution is advised due to the potential for peripheral neuropathy and convulsions, especially at higher doses.

Pharmacokinetics

Metronidazole is well absorbed following oral administration and is distributed widely throughout the body, including the central nervous system. It undergoes hepatic metabolism, primarily through oxidation and conjugation, and is excreted mainly in urine. The pharmacokinetic profile may vary in patients with hepatic impairment, and dosage adjustments may be necessary.

Adverse effects

• Peripheral neuropathy
• Convulsions
• Nausea
• Vomiting
• Diarrhea
• Headache
• Dizziness
• Abdominal cramps
• Metallic taste
• Skin rash

Interactions

• Metronidazole + Coumarins: Increases anticoagulant effect
• Metronidazole + Lithium: Increases concentration
• Metronidazole + Busulfan: Increases risk of toxicity (unknown)
• Metronidazole + Capecitabine: Increases risk of capecitabine toxicity (unknown)
• Metronidazole + Fluorouracil: Increases risk of toxicity (unknown)
• Metronidazole + Alkylating agents: Increases risk of toxicity (unknown)

Precautions

• Caution in patients with history of neurological disorders
• Monitor for signs of peripheral neuropathy
• Use with caution in patients with hepatic impairment
• Avoid excessive alcohol consumption during treatment

Pregnancy

No information available; manufacturer advises avoidance unless essential.

Breast-feeding

Amount in milk probably too small to be harmful.

Storage

Store in a cool, dry place, away from light. Keep out of reach of children.

Formulations

• Metronidazole 0.75% gel
• Metronidazole 0.75% cream
• Metronidazole powder and solvent for nebuliser solution
• Metronidazole injection
• Metronidazole oral tablets (various strengths)

Indications

• Food preservative
• Treatment of urea cycle disorders
• Metabolic disorders involving benzoyl-CoA

Dosage

Children: Refer to the BNF for Children for specific dosing guidelines based on condition.

Adults: Refer to the BNF for specific dosing guidelines based on condition.

Mechanism of action

Benzoate acts mainly by inhibiting the growth of bacteria and fungi through its ability to lower the pH, creating an environment that is less favorable for microbial growth. It is also involved in metabolic pathways where it helps in the conjugation of toxic substances, facilitating their excretion from the body.

Pharmacodynamics

Benzoate is known for its antimicrobial properties, which are particularly effective against a wide range of fungi and bacteria. Its efficacy as a preservative is due to its ability to penetrate microbial cell membranes and disrupt their metabolic processes. Additionally, it has been observed to modulate various metabolic pathways, particularly those associated with aromatic compound degradation.

Pharmacokinetics

After ingestion, benzoate is rapidly absorbed in the gastrointestinal tract. It is metabolized primarily in the liver, where it undergoes conjugation with glycine to form hippurate, which is then excreted in the urine. The half-life of benzoate varies depending on individual metabolic rates but is generally short due to its efficient conversion and excretion.

Pregnancy

There is limited data on the use of benzoate in pregnancy. Consultation with healthcare professionals is advised before use.

Breast-feeding

Limited data is available on the excretion of benzoate in breast milk. Caution is recommended when administering to nursing mothers.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Indications

• Irritable bowel syndrome
• Functional gastrointestinal disorders
• Spasm of the gastrointestinal tract

Dosage

Children: Refer to the BNF for Children for appropriate pediatric dosing guidelines.

Adults: Typically, dicyclomine is administered in doses of 20-40 mg orally, taken 4 times daily, or 10-20 mg by intramuscular injection. Dicyclomine should not be given intravenously.

Mechanism of action

Dicyclomine exerts its effects through direct antimuscarinic activity at M1, M2, and M3 receptors, along with non-competitive antagonism of bradykinin and histamine. This results in a relaxation of smooth muscle, particularly in the ileum, leading to decreased contractions and alleviation of spasms. Its major action is a non-specific direct relaxant effect on smooth muscle rather than a competitive antagonism of acetylcholine.

Pharmacodynamics

Dicyclomine is classified as an anticholinergic drug, which is effective in relaxing smooth muscle in the intestines. Its onset of action provides symptomatic relief in conditions characterized by gastrointestinal spasm and discomfort. The drug is typically dosed multiple times throughout the day, reflecting its moderate duration of action.

Pharmacokinetics

Dicyclomine is absorbed after oral administration, with peak plasma concentrations usually occurring within 1 to 2 hours. It undergoes hepatic metabolism, and its metabolites are excreted primarily in the urine. The half-life of dicyclomine varies but is generally around 1-2 hours, which supports the need for multiple daily dosing.

Contra-indications

• Glaucoma
• Myasthenia gravis
• Severe ulcerative colitis
• Obstructive uropathy
• Severe hepatic impairment

Adverse effects

• Dry mouth
• Dizziness
• Drowsiness
• Nausea
• Constipation
• Blurred vision
• Tachycardia

Interactions

• Other anticholinergic drugs may increase the risk of side effects
• CNS depressants may enhance drowsiness
• Antacids may affect absorption

Precautions

• Use with caution in patients with urinary retention
• May exacerbate existing gastrointestinal obstruction
• Caution in elderly patients due to increased sensitivity to anticholinergics
• Monitor for signs of overdose, especially in children

Pregnancy

Dicyclomine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Consult healthcare professionals for guidance.

Breast-feeding

Dicyclomine may pass into breast milk. Caution is advised when administered to nursing women.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Oral tablet (20 mg, 40 mg)
• Injectable solution (10 mg/2 mL, 20 mg/2 mL)

Indications

• Hypertension
• Heart failure
• Angina pectoris
• Prevention of cardiovascular events

Dosage

Children: Refer to the BNF for Children for appropriate paediatric dosing guidelines.

Adults: Refer to the BNF for specific dosing recommendations based on individual patient factors.

Mechanism of action

Diloxande exerts its effects through selective blockade of alpha-1 and beta-adrenergic receptors. By inhibiting these receptors, diloxande induces vasodilation and reduces heart rate, effectively lowering blood pressure. The drug's action contributes to improved blood flow and reduced workload on the heart.

Pharmacodynamics

The pharmacodynamics of diloxande involve its ability to decrease peripheral vascular resistance and cardiac output. As an antihypertensive, it helps in reducing the heart's workload and oxygen demand, thus providing benefits in conditions like hypertension and heart failure. The onset of action is typically rapid, with effects lasting several hours, depending on the dosing regimen.

Pharmacokinetics

Diloxande is well absorbed after oral administration, with peak plasma concentrations occurring within 1 to 3 hours. The drug undergoes hepatic metabolism, and its metabolites are primarily excreted via urine. The half-life of diloxande is variable but generally ranges from 10 to 20 hours, allowing for once or twice daily dosing in clinical practice. Factors such as age, liver function, and concomitant medications can influence its pharmacokinetic profile.

Pregnancy

Diloxande is not recommended during pregnancy due to insufficient safety data.

Breast-feeding

It is not known whether diloxande is excreted in human breast milk. Caution is advised.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Dosage

Children: Refer to specific drug guidelines, as dosing varies widely based on the hydrochloride formulation.

Adults: Refer to specific drug guidelines, as dosing varies widely based on the hydrochloride formulation.

Mechanism of action

The mechanism of action depends on the specific drug in question, as many different medications can be available as hydrochloride salts. Generally, hydrochloride salts dissociate in solution, allowing the active drug to exert its pharmacological effects by interacting with specific receptors or enzymes in the body.

Pharmacodynamics

Pharmacodynamics varies based on the specific drug. Typically, hydrochloride forms allow for increased solubility and absorption, leading to a more predictable pharmacological response. This can include actions such as receptor agonism or antagonism, enzyme inhibition, or modulation of physiological processes.

Pharmacokinetics

Pharmacokinetics of hydrochloride salts is characterized by improved absorption due to enhanced solubility. The drug's distribution, metabolism, and excretion will depend on its specific properties, including half-life, bioavailability, and route of administration. Specific pharmacokinetic profiles should be referenced for each individual hydrochloride compound.

Contra-indications

• Hypersensitivity to hydrochloride or any component of the formulation
• Severe renal impairment
• Severe liver disease

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Dizziness
• Headache
• Dry mouth
• Fatigue
• Hypotension

Interactions

• May interact with antihypertensive medications leading to additive effects
• Caution when used with other medications that can cause renal impairment

Precautions

• Use with caution in patients with pre-existing renal or hepatic conditions
• Monitor electrolytes, especially in long-term use
• Assess hydration status before initiation

Pregnancy

Use only if the potential benefit justifies the potential risk to the fetus. Consult relevant guidelines.

Breast-feeding

Use with caution, as it is not known whether it is excreted in human milk. Consult relevant guidelines.

Storage

Store in a cool, dry place away from direct sunlight. Keep out of reach of children.

Formulations

• Tablets
• Capsules
• Oral solution
• Injectable solution

Mechanism of action

The exact mechanism of action of metronidazole has not been fully established, however, it is possible that an intermediate in the reduction of metronidazole which is only made by anaerobic bacteria and protozoa, binds deoxyribonucleic acid and electron-transport proteins of organisms, blocking nucleic acid synthesis. After administration, metronidazole enters cells by passive diffusion. Following this, ferredoxin or flavodoxin reduce its nitro group to nitro radicals. The redox potential of the electron transport portions of anaerobic or microaerophilic microorganisms renders metronidazole selective to these organisms, which cause nitro group reduction, leading to the production of toxic metabolites. These include N-(2-hydroxyethyl) oxamic acid and acetamide, which may damage DNA of replicating organisms. Microbicidal; active against most obligate anaerobic bacteria and protozoa by undergoing intracellular chemical reduction via mechanisms unique to anaerobic metabolism. Reduced metronidazole, which is cytotoxic but short-lived, interacts with DNA to cause loss of helical structure, strand breakage, and resultant inhibition of nucleic acid synthesis and cell death. Metronidazole is bactericidal, amebicidal, and trichomonacidal in action. The exact mechanism of action of the drug has not been fully elucidated. Metronidazole is un-ionized at physiologic pH and is readily taken up by anaerobic organisms or cells. In susceptible organisms or cells, metronidazole is reduced by low-redox-potential electron transport proteins (e.g., nitroreductases such as ferredoxin) to unidentified polar product(s) which lack the nitro group. The reduction product(s) appears to be responsible for the cytotoxic and antimicrobial effects of the drug which include disruption of DNA and inhibition of nucleic acid synthesis. Metronidazole is equally effective against dividing and nondividing cells. In in vivo studies in rats given metronidazole in dosages of 2-4 mg/100 g of body weight, the drug reportedly inhibited the development of formalin-induced edema in the rat paw. In vitro in neutrophils, metronidazole has a dose-dependent inhibitory effect on generation of hydrogen peroxide and hydroxyl radicals, oxidants that may cause tissue injury at the site of inflammation. This antioxidant effect appears to be caused by a direct effect on neutrophil function and may contribute to the drug's anti-inflammatory effect in vivo. Results of in vitro studies using leukocytes obtained from patients with Crohn's disease indicate that exposing the cells to metronidazole concentrations of 10 or 50 mcg/mL improved both spontaneous and induced leukocyte migration in cells that previously exhibited reduced migration; the drug had no effect on leukocytes obtained from healthy adults or patients with Crohn's disease when the cells exhibited normal migration prior to exposure to the drug. This effect on leukocyte migration also was observed in vivo in adults with Crohn's disease who received a single 400-mg dose of metronidazole. It has been suggested that metronidazole may increase leukocyte migration by a direct effect on the leukocytes, possibly by causing the release of surface-bound immune complexes from the cell surface.

Pharmacodynamics

Metronidazole treats amebiasis, trichomoniasis, and giardiasis, exerting both antibacterial and antiprotozoal activities. Metronidazole is an effective treatment for some anaerobic bacterial infections. Metronidazole has shown antibacterial activity against the majority of obligate anaerobes, however, during in vitro studies, it does not demonstrate significant action against facultative anaerobes or obligate aerobes. The nitro group reduction of metronidazole by anaerobic organisms is likely responsible for the drug's antimicrobial cytotoxic effects, causing DNA strand damage to microbes. A note on convulsions and neuropathy and carcinogenesis It is important to be aware of the risk of peripheral neuropathy and convulsions associated with metronidazole, especially at higher doses. If convulsions or numbness of an extremity occur, discontinue the drug immediately. Metronidazole has been found to be carcinogenic in mice and rats. The relevance to this effect in humans is unknown. It is advisable to only administer metronidazole when clinically necessary and only for its approved indications.

Mechanism of action

Dicyclomine achieves its action partially through direct antimuscarinic activity of the M1, M3, and M2 receptors; and partially through antagonism of bradykinin and histamine. Dicyclomine non-competitively inhibits the action of bradykinin and histamine, resulting in direct action on the smooth muscle, and decreased strength of contractions seen in spasms of the ileum. ...MAJOR ACTION APPEARS TO BE NONSPECIFIC DIRECT RELAXANT ACTION ON SMOOTH MUSLCE RATHER THAN COMPETITIVE ANTAGONISM OF ACH.

Pharmacodynamics

Dicyclomine is an anticholinergic drug used to relax the smooth muscles of the intestines. It's duration of action is not especially long as it is usually taken 4 times daily with individual doses of 20-40mg orally or 10-20mg by intramuscular injection. Dicyclomine should not be administered intravenously.